The invention relates in general to munitions and in particular to seeker and/or fuze setting type or “smart” munitions.
Some gun launched cartridges, such as 120 mm cartridges, include onboard electronics for guidance and/or fuzing. Prior to firing these cartridges, data and/or electrical power are transferred to the projectile using a data link. The data can include firing platform and downrange targeting information. Data transmission is initiated by the weapon's fire control system and transmitted through the breech of the gun into the cartridge. A known data link is embedded in the primer, which is inserted into the standard 120 mm case base assembly. The data transmission point is the standard 120 mm firing pin. The case base itself provides the electrical ground necessary to complete the electrical firing circuit when the breech block is in the closed position.
In the primer based data link, the data transmission circuit and the weapon's electrical firing circuit are the same. Thus, data transmission is susceptible to line noise from the firing circuit. Furthermore, there is some risk of unintended firing of the cartridge during data transmission. There is a need for a data link for a cartridge that is separate from the firing circuit for the cartridge.
It is an object of the invention to provide a gun launched cartridge having a data link that is isolated from the firing circuit and having two way communications between the weapon's fire control system and the cartridge while inside the gun chamber.
One aspect of the invention is a cartridge case comprising a cartridge case base having a bottom surface, a primer and an annular recess formed in the bottom surface, the annular recess being concentric with the primer; first and second concentric conductive rings disposed in the annular recess, the first and second rings being radially spaced apart and substantially flush with the bottom surface of the cartridge case base, the first and second rings being electrically insulated from the cartridge case base and the primer; a first data pin electrically connected to the first conductive ring and extending into an interior of the cartridge case base; and a second data pin electrically connected to the second conductive ring and extending into the interior of the cartridge case base, the first and second data pins being electrically insulated from the cartridge case base.
The invention will be better understood, and further objects, features, and advantages thereof will become more apparent from the following description of the preferred embodiments, taken in conjunction with the accompanying drawings.